The first stage in the development of phenylglyoxal-bis(4-methyl thiosemicarbazone) copper and zinc chelates as antineoplastic agents has resulted in computerized multiparameter regression analyses indicating that inhibition of Ehrlich ascites cell respiration can be increased by increased by more water soluble chelates with electron donating groups on the phenyl ring. A comparative analysis shows that this would also decrease toxicity to liver slice respiration. An additional series of phenylglyoxal - bis(4-methyl thiosemicarbazone) copper and zinc chelates possessing the properties indicated by the analyses has been designed and will be synthesized and tested for its ability to inhibit ascites cell respiration and liver slice respiration. The results of the testing of the new molecules will be combined with the initial series to improve the quality of the regression equations. This should allow prediction of the optimal solubility characteristics for transport into the ascites cell vs. the liver cell and thus provide a physicochemical characterization of cell membrane properties on a quantitative comparative basis. In addition, a series of zinc chelates of substituted phenylglyoxal - bis (4,4-dimethyl thiosemi-carbazones) has been designed for preliminary analysis.